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<p style="margin-top: 0px; margin-bottom: 0px;"><font face="monospace">MatPtAP with A=I gives Pt*P, not P*Pt. We have sequential MatRARt and MatMatTransposeMult(), but no support for mpiaij matrices. The problem is that we do not have a way to implement C*Ct
without explicitly transpose C in parallel.</font></p>
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<p style="margin-top: 0px; margin-bottom: 0px;"><font face="monospace">We support MatTransposeMatMult (A*Bt) for mpiaij. Can you use this instead? </font></p>
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<p style="margin-top: 0px; margin-bottom: 0px;"><font face="monospace">Hong</font></p>
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<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> petsc-users <petsc-users-bounces@mcs.anl.gov> on behalf of Zhang, Hong via petsc-users <petsc-users@mcs.anl.gov><br>
<b>Sent:</b> Thursday, September 24, 2020 8:56 AM<br>
<b>To:</b> Matthew Knepley <knepley@gmail.com>; Mark Adams <mfadams@lbl.gov><br>
<b>Cc:</b> PETSc <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] Compute C*Ct using MatCreateTranspose for Ct</font>
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Indeed, we do not have <span style="color:rgb(50,49,48); font-size:17px; font-weight:600; background-color:rgb(250,249,248); display:inline!important">MatCreateTranspose for mpaij matrix. </span></div>
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<span style="color:rgb(50,49,48); font-size:17px; font-weight:600; background-color:rgb(250,249,248); display:inline!important">I can adding such support. How soon do you need it?</span></div>
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<span style="color:rgb(50,49,48); font-size:17px; font-weight:600; background-color:rgb(250,249,248); display:inline!important">Hong</span></div>
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<div id="x_divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> petsc-users <petsc-users-bounces@mcs.anl.gov> on behalf of Matthew Knepley <knepley@gmail.com><br>
<b>Sent:</b> Thursday, September 24, 2020 6:12 AM<br>
<b>To:</b> Mark Adams <mfadams@lbl.gov><br>
<b>Cc:</b> PETSc <petsc-users@mcs.anl.gov><br>
<b>Subject:</b> Re: [petsc-users] Compute C*Ct using MatCreateTranspose for Ct</font>
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<div dir="ltr">On Thu, Sep 24, 2020 at 6:48 AM Mark Adams <<a href="mailto:mfadams@lbl.gov">mfadams@lbl.gov</a>> wrote:<br>
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Is there a way to avoid the explicit transposition of the matrix?</tt></p>
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<div>It does not look like we have A*B^T for mpiaij as the error message says. I am not finding it in the code.</div>
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<div>Note, <span style="font-family:monospace">MatMatMult with a transpose shell matrix, I suspect that it does an explicit transpose internally, or it could notice that you have C^T*C and we might have that implemented in-place (I doubt it, but it would be
legal and fine to do).</span></div>
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<div>We definitely have</div>
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<div> <a href="https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatPtAP.html">https://www.mcs.anl.gov/petsc/petsc-current/docs/manualpages/Mat/MatPtAP.html</a></div>
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<div>For now, you can put the identity in for A. It would be nice it we assumed that when A = NULL.</div>
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<div>Patrick, the implementation strategy is broken for the MatProduct mechanism that was just introduced, so</div>
<div>we cannot see which things are implemented in the documentation. How would I go about fixing it?</div>
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<div> Thanks,</div>
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<div> Matt</div>
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<p><tt>Many thanks,</tt><tt><br>
</tt><tt>Olivier Jamond</tt><br>
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<div>What most experimenters take for granted before they begin their experiments is infinitely more interesting than any results to which their experiments lead.<br>
-- Norbert Wiener</div>
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<div><a href="http://www.cse.buffalo.edu/~knepley/" target="_blank">https://www.cse.buffalo.edu/~knepley/</a><br>
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